1. Field of the Invention
This invention relates to the field of absorbent articles in general, and more particularly to absorbent articles that provide improved leakage protection. The invention also relates to methods for using and preparing absorbent articles having improved leakage protection, methods for designing articles having improved leakage protection, and methods of measuring and determining the performance index of an absorbent article.
2. Description of Related Art
Disposable absorbent articles typically include a moisture-impervious backing sheet, an absorbent pad, and a moisture permeable liner sheet (e.g., top sheet) that contacts the body of a person wearing the article. In addition, elasticized regions are provided around the edges of the article to secure the article about the waist and legs of a wearer. Diapers typically further comprise opposed front and rear waist portions defining a waist opening, a crotch portion disposed there between, and a pair of elastically contractible leg openings along the side edges of the crotch portion. Disposable diapers having elasticized margins for placement about the legs of a wearer are disclosed in U.S. Pat. No. 4,050,462 and U.S. Pat. No. 5,092,861. An absorbent article having elasticized side margins and waist band margins are shown in U.S. Pat. No. 4,300,562. These elasticized portions of the garment typically are designed to contain body exudates and hence, prevent leakage.
Despite previous advancements in the field of absorbent articles, the art continuously strives to produce more comfortable garments that are better able to contain urinary and fecal excretions. For instance, problems with prior diaper designs include leakage of urinary or fecal material from the garment. Prolonged contact of liquid or semi-solid excreta with the skin of the wearer also is a continuing problem in the art because the moisture vapor and heat generated by the body exudates trapped within a diaper may lead to conditions adjacent to the wearer's skin that promote skin irritation, infection, and the like. Although the top sheet, as described above, is generally effective in allowing the passage of bodily exudates outwardly, the moisture permeable nature of top sheets may result in leakage of liquids. Various approaches have been attempted to address the lateral leakage of liquids from absorbent articles.
For example, U.S. Pat. No. 6,114,596 discloses a breathable diaper, feminine hygiene, or like disposable sanitary product having a cloth-like outer surface and including a plurality of materials from the skin-facing side outwardly, a selectively-permeable top sheet, a core, an optional barrier, and a back sheet. The disclosed optional barrier is formed from a multi-layer non-woven material that is hydrophobic and vapor-permeable for limiting the outward escape of liquid there through while enabling the outward escape of heat and water vapor there through. The disclosed barrier has a base disposed adjacent the core outer surface. The disclosed back sheet is formed of a multi-layer non-woven material that is hydrophobic and vapor permeable for limiting the outward escape of liquid there through while enabling the outward escape of heat and water vapor there through. This back sheet is disclosed as being disposed at least partially as an outer surface of the diaper.
U.S. Pat. No. 6,017,336 discloses an absorbent article that includes a pair of compression resistant containment barriers that are configured to inhibit the lateral flow of fecal exudates along the surface of the absorbent article. The containment barriers are disclosed as being laterally spaced apart to provide a void space between the wearer's back side and the surface of the absorbent article for containing body exudates. The absorbent article is disclosed as optionally including a containment dam that is located on the body facing surface of the absorbent article and is configured to inhibit a longitudinal flow of fecal exudates along the surface of the absorbent article.
U.S. Pat. No. 5,597,906 discloses an absorbent article comprising a liquid pervious top sheet, a liquid pervious back sheet joined to at least a portion of the top sheet, an absorbent core disposed between at least a portion of the top sheet and the back sheet, and a waste management element disposed in at least a portion of the crotch region. The waste management element preferably has an acceptance under pressure value of greater than about 0.50 grams of a viscous fluid bodily waste per square inch of the waste management element. The waste management element also is disclosed as having a storage under pressure value of at least about 0.70 grams of the viscous fluid bodily waste per square inch of the waste management element. The waste management element also is disclosed as optionally having an Immobilization Under Compressed Inversion value of greater than about 70% of the viscous fluid bodily waste accepted by the waste management element. The waste management element is disclosed as being located anywhere in the article, including the crotch region.
U.S. Pat. No. 5,941,864 discloses a disposable absorbent article, such as a diaper having a first top sheet with apertures large enough for low-viscosity fecal material to pass through to a fecal material storage element. The fecal material storage element is disclosed as immobilizing the fecal material in position for dewatering, so that the liquid components of the fecal material are absorbed by the core and solid components of the fecal material are separated from the liquid components, to provide for easier cleaning of the wearer when the soiled disposable absorbent article is removed.
U.S. Pat. No. 6,040,251 discloses barrier webs having certain desirable physical qualities such as water resistance, increased durability, improved barrier qualities, and the like. Barrier webs are disclosed as comprising a web that has been treated with a curable shear thinned thixotropic polymer composition that is adapted to be substantially impermeable to liquids, permeable to gases and impermeable to microorganisms. Further, the barrier webs are disclosed as being either impermeable to all microorganisms or impermeable to microorganisms of certain sizes. Also disclosed are fabrics that are capable of either selectively binding certain microorganisms, particles, or molecules depending upon what binding partners are incorporated into the polymer before application to the fabric.
U.S. Pat. No. 6,117,121 discloses an absorbent article including an absorbent core located between a body-side liner and an outer cover. The absorbent article is disclosed as having a leg cuff mounted to a base structure in the crotch portion thereof. The leg cuffs are disclosed as being partially stretched when attached to respective longitudinal side portions near the crotch portion of the absorbent article.
U.S. Pat. No. 6,107,539 discloses disposable absorbent articles comprising a back sheet, a top sheet, a fluid acquisition/distribution region and at least one fluid storage region, the article having a total product acquisition performance of more than 3.75 ml/sec in the first gush and more than 0.5 ml/sec in the fourth gush and an in bag stack height of less than 9.9 mm. The article is characterized in that the top sheet allows it to retain no more then 0.25 g of fluid as measured by the top sheet-on-acquisition-material-wetness test, and that the acquisition/distribution region has a drip capacity of at least 5.0 grams of fluid per gram of material.
U.S. Pat. No. 5,683,809 discloses protective articles such as diapers, having film-less hydrophobic barrier elements such as cuffs and backing sheets. The barrier cuffs—which can be, for instance, leg cuffs and waistbands—and the backing sheets can be provided from fabrics having a fabric weight of at least 10 g/y2.
U.S. Pat. No. 5,817,079 discloses absorbent products, such as sanitary napkins, discreet areas of dry fibrous materials such as fluid-repellent materials are precisely placed in various planes within the product so as to provide barriers to bodily fluid leakage from the product. In a preferred embodiment, hydrophobic fibers are placed around the periphery of a central absorbent area of an absorbent product to discourage and/or prevent side or end leakage from the product.
As is apparent from the foregoing, there are a variety of mechanisms for controlling leakage in absorbent garments. However, all of these proposed means are deficient in terms of effectiveness and low product quality, mechanical complexity in design, and/or associated cost inefficiencies.
The description herein of the various known products, methods, and apparatus and their attendant disadvantages is in no way intended to limit the scope of the present invention, or to imply that the present invention does not include some or all of the various elements of the products, methods, and apparatus in one form or another. Indeed, various embodiments of the invention may be capable of overcoming some of the disadvantages noted herein, while still retaining some or all of the various elements of the known products, methods, and apparatus in one form or another.
All documents described herein are incorporated by reference in this disclosure in their entirety.